This invention relates to an improved table shear having a clamp mechanism for preventing movement of the metal plate to be cut during the shearing process.
Table shears or plate cutters are typically utilized to cut pieces of metal in precise dimensions for subsequent use in the manufacture of trophy columns or other metal objects. A conventional table shear includes a table having a table blade on one end thereof, a raised rule along the length of the table for measuring the metal plate to be cut, a cutting blade, and a leverage mechanism for driving the cutting blade downward in proximity to the table blade. As the cutting blade is driven downward, it slices the metal plate from one edge of the plate to the opposite edge.
It is very important that the metal plate be cut in precise dimensions; if not, intolerances may impede the proper manufacture of an object with the cut pieces of metal. However, the initial downward cutting action of the blade at an angle, perpendicular to the plate, typically causes the metal plate to move or shift, thereby causing the blade to cut the plate along an undesired line of cut. In addition to minimizing plate movement, it is also important that the table shear have a safety guard to protect the operator's hands and fingers during the cutting process.
Prior attempts to alleviate the shifting of the metal sheet during the initial cutting stage of a table shear have included the use of a plurality of spring activated clamps. Such clamps must initially be attached to the cutting blade support with the metal plate thereafter placed beneath each of the spring loaded legs. After the plate is cut, each of the legs must be raised to permit removal of the metal piece. Since the spring activated clamps operate independent of the cutting blade leverage mechanism, their use is cumbersome, time consuming, and not deemed to provide sufficient shifting impedance. Various types of safety guards or blade shields have also been developed.